The present invention is directed to an expansion dowel assembly and to a method of anchoring the assembly in a borehole. The assembly includes a radially expandable member with first means engageable with the expandable member for applying a load to the assembly. The first means is axially displaceable relative to the expandable member during the expanding operation.
Expansion dowel assemblies of the above-mentioned type have a after-expansion characteristic and, therefore, are used chiefly for medium and heavy load applications. During the after-expansion, the radial expansion of the expandable member and, as a result, the anchoring value of the expansion dowel assembly increases. To achieve expansion of the dowel assembly, the dowel assembly must be secured in the borehole against axial displacement.
In DE-OS 2 205 289 it is known to secure an expansion sleeve in a borehole by means of a cementing material. Such a solution, however, has various disadvantages. For example, the borehole must be carefully cleaned prior to the insertion of the dowel assembly so that the cemented anchorage can be developed. Furthermore, a cemented anchorage requires a certain time period to set or cure and during such period the dowel assembly can not be loaded.